Abstract: First image data is obtained by performing an image capturing operation with a flash and, subsequently, second image data is obtained by performing an image capturing operation without a flash. By using data of a differential image between the first and second image data and a relative spectral distribution of flash light, the spectrum reflectivity in a position on a subject corresponding to each pixel is obtained and object-color component data is acquired as data from which an influence of an illumination environment has been removed. On the other hand, illuminant component data indicative of spectral distributions of a plurality of illumination light are prepared. By combining arbitrary illuminant component data to the obtained object-color component data, an image with a different illumination environment can be reproduced.

Abstract: Colorimetric values such as L*a*b* are input from an input section to a color gamut mapping portion. A filtering process is performed on an image of the difference between the image sent by the input section and an image obtained as a result of bi-directional conversion at a converter section, and the input to the converter section is controlled so as to satisfy a requirement of minimizing an evaluation function which is defined by the sum of square norm of the filtered image as a whole and a value obtained by performing a thresholding process on norm of the difference in each pixel between images before and after the conversion at the converter section output by a gamut extracting section, obtained for the image as a whole. Device values satisfying predetermined conditions which are output of a first neural network of a first converter section to an image output section.

Abstract: A color correcting unit receives color separation values such as CMY values from an image input unit. Under the control of a control portion, inputs to a first conversion portion constituted by a neural network which has been trained in advance on the basis of the spectral distribution of an arbitrary illuminant are corrected so that outputs from the first conversion portion satisfy the color separation values and a predetermined requirement. The input values to the first conversion portion, which satisfy the predetermined requirement, are sent to an image output unit. The image output unit outputs an image in accordance with these input values.

Abstract: A color balance adjusting apparatus for adjusting color imbalance due to the difference in color temperature between a preferable standard illuminant and an illuminant under which a color image is obtained, thereby making the colors of the image substantially identical to those obtained under the preferable standard illuminant. This apparatus comprises a decorrelating neural network for receiving three color component signals correlating with one another and indicative of an image, and minimizing the correlation thereamong, the network having learned so as to minimize the correlation among signals indicative of an image obtained under an illuminant, and a converter for mapping the output of the decorrelating means, into a space of the input image signals, with the use of the inverse matrix of a transfer matrix of the neural network having learned under the preferable standard illuminant. The output of the converter is generated as a signal obtained after white balance adjusting.

Abstract: To practice a method of transforming color sensation informations such that multidimensional physical informations and color sensation informations sensed by living bodies in response to the physical informations are non-linearly transformed therebetween, a multilayer feedforward type neural network is used for the purpose of accomplishing the foregoing transformation. The physical informations are provided in the form of data derived from multidimensional spectral distribution of light and the color sensation informations are provided in the form of sensitive colors each sensed by the living bodies as a psychological quantity relative to a certain color.

Abstract: A method of separating an oscillatory potential wave from an electroretinogram of a subject which contains an "a" wave, a "b" wave and said oscillatory potential wave that overlap each other. The electroretinogram ([1]) is produced by light stimulation to the retina of an eye of the subject, and is detected by a suitable device. The peak-to-peak distances of the detected electroretinogram are determined, and a mean period (T) of the oscillatory potential wave ([10]) to be separated from said electroretinogram is obtained. Then, a tentative start point (A) of the oscillatory potential wave is determined, and an OP-free waveform ([7], [9]) free of said oscillatory potential wave is obtained by obtaining moving averages of a first intermediate waveform ([6], [8]) which is determined based on the electroretinogram and the determined tentative start point (A). The oscillatory potential wave ([10]) is extracted by subtracting the OP-free waveform ([7], [9]) from the electroretinogram ([1]).

Abstract: A digital signal processing apparatus is disclosed. A delay circuit generates (2p+1) signals x.sub.k-n to x.sub.k+n (n=0, 1, 2, . . . , p), each having a difference respective delay time. The apparatus further comprises a computation circuit responsive to the foregoing signal for computing ##EQU1## wherein coefficients j and h.sub.0 to h.sub.n are ".+-.1" and "1" or "0", respectively.